Electrical switching devices, such as compact circuit breakers, have the task of uncoupling a number of consumers from a power supply network if a specific fault occurs. The classical fault is the occurrence of a short-circuit current and the circuit breakers are conventionally configured to move a switching element in such a short circuit current and thus to decouple the connection between the consumers and the network.
With such electrical switching devices, in the event of a tripping process determined by the short circuit or a manual tripping under load, an arc may occur between two contacts which are separated hereby, and may result in their destruction or in damage to the electrical switching device. To ensure that any arc that occurs can be discharged in a targeted manner, electrical switching devices of this type comprise arch extinguishing apparatuses.
Gases or plasma can develop with the arc within the arc extinguishing apparatus of the electrical switching device, in particular within an extinguishing chamber of the arc extinguishing apparatus, which is/are generated by the high energy density of the arc. This results in a rapid increase in pressure in the housing of the electrical switching device. In order to prevent the pressure increase, the developing gases and/or the developing plasma are blown out of the housing of the electrical switching device. A blow-out channel is provided for this purpose, which is arranged in particular at the end of the arc extinguishing apparatus or at an end of an extinguishing chamber of the arc extinguishing apparatus, which faces away from the contacts of the electrical switching device. The blow-out channel can open out on one side or at the rear side of the electrical switching device.
It is therefore known for instance with electrical switching devices such as compact circuit breakers with double break contacts, that the plasma produced in the event of a short circuit on one side of the electrical switching device is siphoned out below the terminal strips, in other words the terminal on the customer side. The installation space involved in connection technology, in particular the rear connection technology, is herewith restricted and significantly reduced in the event of the connection technology of the blow-out cross-section on the rear side.
With some compact circuit breakers, the problem is solved by them routing the plasma through a contour molded in the housing lower part to the connection technology. The blow-out cross-section of the blow-out channel available is as a result significantly restricted and the remaining installation space is exclusively available for the rear connection technology.
Compact circuit breakers also exist, which guide the rear connection technology rearwards outside of the switch contour, however the installation space of the electrical switching device is significantly enlarged as a result.